Off-shore oil exploration and drilling operations present potentially serious sources of water pollution. A break in a well casing at or near the ocean floor or a crack or fissure in the subterranean rock structure adjacent an existing well, due to pressure build-up, will often cause a serious oil and gas leakage which can be extremely difficult to control. In the past containment receptacles have been devised which cooperates with the sea bottom to provide a substantial enclosure around a source of leakage and which includes a means for pumping or otherwise removing oil or water contaminated with oil from the enclosure. A typical containment receptacle is shown in U.S. Pat. No. 3,681,923, to Hyde, which describes steps of collecting oil within an underwater receptacle located along the sea floor. The open-bottom receptacle overlies a leak. A conduit is connected to the receptacle. A concrete seal is lowered and placed along the sidewall of the containment vessel adjacent to the ocean floor.
U.S. Pat. No. 4,318,442 to Lunde, et al. describes a vessel with a lower weighted collar (i.e., base loop), that serves as ballast. Provided on the vessel are vent ports, a valve controlled chimney, a gas outlet positioned to provide a gas cap in the vessel when the valve is closed with the vessel in position around the blowing well, and an oil outlet above the vent ports and below the gas cap and means for pumping substantially only oil from the vessel at a rate to prevent oil from escaping from the vessel to the sea in substantial quantities.
U.S. Pat. No. 4,456,071 to Milgram describes a collector vessel for use with a blown-out seabottom wellhead. The vessel has a conical base with a flanged open bottom and a cylindrical riser extending from the top of the base. A loop-like level pad is installed about the wellhead. The flange of the vessel is attached to the pad by means of skirt piles. This forms a seal against leakage. The vessel includes a relief passage adapted to vent excess gas from the collector apparatus during initial stages of any blow-out. A valve in the relief passage allows the passage to be closed after the initial stages of any blow-out to limit escape of released oil. The vessel includes a drilling port adapted to allow drilling operations to proceed.
The prior art systems and methods do not effectively anchor the containment vessel into place. None of the prior art systems and methods teach or enable a containment vessel at least partially embedded in a concrete base. Likewise, none of the prior art systems and methods teach pumping concrete as part of the vessel installation process, or use of a loop-like frame in which the concrete base will be formed.
Additionally, the prior art systems and methods do not effectively accommodate an irregular seabed. The prior art may work well where the seabed is relatively planar or at least conforms to the shape of the containment vessel and ballast. However, non-planar, non-conforming seabeds cause gaps between ballast and the seabed or the containment vessel and the seabed. Such gaps are conducive to continued leakage.
Furthermore, the prior art systems and methods are not scalable or adaptable accommodate a wide range of leakage sources, such as fissures, a broken well pipe, a failed blowout preventer, a failed annular or other similar equipment. Instead, the prior art systems and methods are intended to address a particular leak source under particular conditions.
Moreover, the prior art systems and methods do not address pressure relief and removal of ice from the containment vessel during installation. Instead, the prior art systems and methods assume that the vessel may be positioned despite the extreme pressure exerted by the escaping fluid. The prior art systems and methods also do not provide means for evacuating ice formations from the interior of the containment vessel. Rapid expansion of escaping gasses (e.g., methane) causes ice formations, which can fill and/or clog a containment vessel, rendering it useless.
The invention is directed to overcoming one or more of the problems and solving one or more of the needs as set forth above.